Waiau River

Waiau River looking east from Hanmer Springs along the Hope Valley towards the Spenser Mountains (top right)

Several tributaries feed into the river. The Lewis River, which parallels sections of the main highway from Canterbury to the West Coast across the Main Divide, the Doubtful River, which joins the Waiau at Amuri Pass, the Hope River, and the Hanmer, Mason, and Leader Rivers. The landscape of the headwaters upstream of the Waiau-Hope junction was glaciated until around 10,000 years ago, providing the rich supply of gravels need for a braided river. The east-west sections of the Hope, Waiau, and Hanmer Rivers lie along the Hope Fault, a major geological feature of the South Island. At Glen Wye Station, the 1888 earthquake broke and displaced fences 2.5m horizontally across the fault. This was the first conclusive evidence in the world of horizontal fault movements.

Waiau River, Hope Valley near Hanmer Springs

Crossing the southern edge of the Hanmer Plains, the Waiau River flows through a gorge to emerge onto the northern part of the Culverden Plains. Before reaching the sea, the river cuts through two more gorges, both of which have been investigated as possible sites for hydro-electric dams. The Waiau River enters the Pacific just north of Cheviot township. Typical of braided rivers, it forms a small lagoon and estuary system at the river mouth.

* ‘Main Divide’ refers to the area of the Southern Alps that divides the water catchments of the eastern side of the island from those on the west coast. The Main Divide also forms the boundary between the Canterbury and West Coast Regions.